I grew up in Peoria and graduated from Bradley.
I think it was a great place to live. The cost of living is low, the running scene is respectable for such a small city (the place where I live now is 8 x as big and is on par), and for a simple redneck like me who isn't totally into the cultural side of life it had everything I needed and desired.
I live in a much bigger city now, and have lived across the midwest and southwest, but I would go back to Peoria in a heartbeat.
There are some great places to run in the town, there is the Steamboat Classic, and it's in close enough proximity to enough of the major cities of the midwest that if you get the itch to either race or hang out someplace larger it can be had with a short drive.
IVS is a great running club for a small city. My family and I have been members for 20 years at this point, and there are plenty of opportunities to get involved.
You aren't going to find an old house on the north side. You could move out to "the country" or live in one of the smaller towns that are in the area. You have to watch the school districts when you get out of the city, though. Dunlap is very good, but Chillicothe IVC (where you can go depending on which side of a neighborhood you live on) is not.
There are MANY churches in town of varying sizes and denominations. Depending on what you are interested in, I'm sure there's something to fit your needs.
Peoria gets a lot of grief it doesn't deserve, as long as you don't go in expecting many of the perks of a larger, more culturally oriented city. It's a simple town for simple rednecks like me (I know I've said that, but I want to reiterate the point), so just realize what you are getting yourself into, and you won't be dissappointed.